06e71650 (community/darktable: build with -O2 to fix build,
2021-07-28) tried to fix the segfault, but setting CXXFLAGS does not
Setting CFLAGS does suffice, so set -O2 via CFLAGS.
create patch by reverting upstream commit
09b8cc7810587257e5f82080884001301e1a1ba9 which made cros_ec not detected
until a new tag/version is created upstream:
Advanced color picker written in C++ using GTK+ toolkit